Comma operator in FROM clause - what is this?

I know how it functions, but what does this mean exactly, and where can
I find it in the books online?
SELECT *
FROM Table1, Table2
What is the name of that Comma's function?
Thanks,
JeremyMost often, this is what we consider an old style join, which you forgot to
restrict. Old style
join, as in
SELECT ...
FROM titles AS t, publishers AS p
WHERE t.pub_id = p.pub_id
Above is the same query as:
SELECT ...
FROM titles AS t
JOIN publishers AS p ON t.pub_id = p.pub_id
No, if you remove the WHERE clause from the first query, you get all rows fr
om titles, combined with
all rows from publihers. In most cases, a meaningless result. We call this c
artesian product, cross
join or unrestricted join. You can accomplish this using the new join syntax
as:
SELECT ...
FROM titles AS t CROSS JOIN publishers AS p
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://www.solidqualitylearning.com/
Blog: http://solidqualitylearning.com/blogs/tibor/
"Jeremy Cowles" <jeremy.cowles@.gmail.com> wrote in message
news:1134662287.068773.293050@.g49g2000cwa.googlegroups.com...
>I know how it functions, but what does this mean exactly, and where can
> I find it in the books online?
> SELECT *
> FROM Table1, Table2
>
> What is the name of that Comma's function?
> Thanks,
> Jeremy
>|||The comma is simply a delimiter. In your from clause you can list all the
tables/views/in line views you are accessing, seperated by commas, then
define your join criteria in the where clause. If you have no join criteria
then the result is a cartesion product (every row in table 1 is joined with
every row in table 2).
"Jeremy Cowles" <jeremy.cowles@.gmail.com> wrote in message
news:1134662287.068773.293050@.g49g2000cwa.googlegroups.com...
> I know how it functions, but what does this mean exactly, and where can
> I find it in the books online?
> SELECT *
> FROM Table1, Table2
>
> What is the name of that Comma's function?
> Thanks,
> Jeremy
>|||Spanx!